// Problem: 
// Contest: 
// URL: 
// Memory Limit: 
// Time Limit: 
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read(){
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
	return s*w;
}
signed main()
{
	int t=1;
	cin>>t;
	while(t--)
	{
		string s,s1,s2;
		int x;
		//getline(cin,s);
		cin>>s1>>s2>>x;
		x*=60;
		s=s1+" "+s2;
		istringstream ss(s);
		tm t;
		ss>>get_time(&t,"%Y-%m-%d %H:%M:%S");
		time_t sta=mktime(&t);
		time_t z=sta-sta%x;
		tm* ta=localtime(&z);
		ostringstream oss;
		oss << put_time(ta,"%Y-%m-%d %H:%M:%S");
		string ans=oss.str();
		cout<<ans<<endl;
	}
	return 0;
}
